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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: Change.html 842 2015-03-07 18:20:42Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.change;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import org.jsimpledb.JObject;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import org.jsimpledb.JTransaction;<a name="line.11"></a>
<span class="sourceLineNo">012</span><a name="line.12"></a>
<span class="sourceLineNo">013</span>/**<a name="line.13"></a>
<span class="sourceLineNo">014</span> * Object change notification.<a name="line.14"></a>
<span class="sourceLineNo">015</span> *<a name="line.15"></a>
<span class="sourceLineNo">016</span> * @param &lt;T&gt; the type of the object that changed<a name="line.16"></a>
<span class="sourceLineNo">017</span> */<a name="line.17"></a>
<span class="sourceLineNo">018</span>public abstract class Change&lt;T&gt; {<a name="line.18"></a>
<span class="sourceLineNo">019</span><a name="line.19"></a>
<span class="sourceLineNo">020</span>    private final T jobj;<a name="line.20"></a>
<span class="sourceLineNo">021</span><a name="line.21"></a>
<span class="sourceLineNo">022</span>    /**<a name="line.22"></a>
<span class="sourceLineNo">023</span>     * Constructor.<a name="line.23"></a>
<span class="sourceLineNo">024</span>     *<a name="line.24"></a>
<span class="sourceLineNo">025</span>     * @param jobj Java model object that changed<a name="line.25"></a>
<span class="sourceLineNo">026</span>     * @throws IllegalArgumentException if {@code jobj} is null<a name="line.26"></a>
<span class="sourceLineNo">027</span>     */<a name="line.27"></a>
<span class="sourceLineNo">028</span>    protected Change(T jobj) {<a name="line.28"></a>
<span class="sourceLineNo">029</span>        if (jobj == null)<a name="line.29"></a>
<span class="sourceLineNo">030</span>            throw new IllegalArgumentException("null jobj");<a name="line.30"></a>
<span class="sourceLineNo">031</span>        this.jobj = jobj;<a name="line.31"></a>
<span class="sourceLineNo">032</span>    }<a name="line.32"></a>
<span class="sourceLineNo">033</span><a name="line.33"></a>
<span class="sourceLineNo">034</span>    /**<a name="line.34"></a>
<span class="sourceLineNo">035</span>     * Get the Java model object containing the field that changed.<a name="line.35"></a>
<span class="sourceLineNo">036</span>     *<a name="line.36"></a>
<span class="sourceLineNo">037</span>     * &lt;p&gt;<a name="line.37"></a>
<span class="sourceLineNo">038</span>     * Although not declared as such to allow flexibility in Java model types, the returned object<a name="line.38"></a>
<span class="sourceLineNo">039</span>     * will always be a {@link JObject} instance.<a name="line.39"></a>
<span class="sourceLineNo">040</span>     * &lt;/p&gt;<a name="line.40"></a>
<span class="sourceLineNo">041</span>     *<a name="line.41"></a>
<span class="sourceLineNo">042</span>     * @return the changed object<a name="line.42"></a>
<span class="sourceLineNo">043</span>     */<a name="line.43"></a>
<span class="sourceLineNo">044</span>    public T getObject() {<a name="line.44"></a>
<span class="sourceLineNo">045</span>        return this.jobj;<a name="line.45"></a>
<span class="sourceLineNo">046</span>    }<a name="line.46"></a>
<span class="sourceLineNo">047</span><a name="line.47"></a>
<span class="sourceLineNo">048</span>    /**<a name="line.48"></a>
<span class="sourceLineNo">049</span>     * Get the Java model object containing the field that changed.<a name="line.49"></a>
<span class="sourceLineNo">050</span>     *<a name="line.50"></a>
<span class="sourceLineNo">051</span>     * &lt;p&gt;<a name="line.51"></a>
<span class="sourceLineNo">052</span>     * This is a convenience method, equivalent to:<a name="line.52"></a>
<span class="sourceLineNo">053</span>     * &lt;blockquote&gt;&lt;code&gt;<a name="line.53"></a>
<span class="sourceLineNo">054</span>     * (JObject)getObject()<a name="line.54"></a>
<span class="sourceLineNo">055</span>     * &lt;/code&gt;&lt;/blockquote&gt;<a name="line.55"></a>
<span class="sourceLineNo">056</span>     *<a name="line.56"></a>
<span class="sourceLineNo">057</span>     * @return the changed object as a {@link JObject}<a name="line.57"></a>
<span class="sourceLineNo">058</span>     */<a name="line.58"></a>
<span class="sourceLineNo">059</span>    public JObject getJObject() {<a name="line.59"></a>
<span class="sourceLineNo">060</span>        return (JObject)this.jobj;<a name="line.60"></a>
<span class="sourceLineNo">061</span>    }<a name="line.61"></a>
<span class="sourceLineNo">062</span><a name="line.62"></a>
<span class="sourceLineNo">063</span>    /**<a name="line.63"></a>
<span class="sourceLineNo">064</span>     * Apply visitor pattern. Invokes the method of {@code target} corresponding to this instance's type.<a name="line.64"></a>
<span class="sourceLineNo">065</span>     *<a name="line.65"></a>
<span class="sourceLineNo">066</span>     * @param target visitor pattern target<a name="line.66"></a>
<span class="sourceLineNo">067</span>     * @param &lt;R&gt; visitor return type<a name="line.67"></a>
<span class="sourceLineNo">068</span>     * @return value returned by the selected method of {@code target}<a name="line.68"></a>
<span class="sourceLineNo">069</span>     */<a name="line.69"></a>
<span class="sourceLineNo">070</span>    public abstract &lt;R&gt; R visit(ChangeSwitch&lt;R&gt; target);<a name="line.70"></a>
<span class="sourceLineNo">071</span><a name="line.71"></a>
<span class="sourceLineNo">072</span>    /**<a name="line.72"></a>
<span class="sourceLineNo">073</span>     * Apply this change to the given object in the given transaction.<a name="line.73"></a>
<span class="sourceLineNo">074</span>     *<a name="line.74"></a>
<span class="sourceLineNo">075</span>     * @param jobj the target object to which to apply this change<a name="line.75"></a>
<span class="sourceLineNo">076</span>     * @param jtx the transaction in which to apply this change<a name="line.76"></a>
<span class="sourceLineNo">077</span>     * @throws NullPointerException if {@code jtx} or {@code jobj} is null<a name="line.77"></a>
<span class="sourceLineNo">078</span>     * @throws org.jsimpledb.core.DeletedObjectException if {@code jobj} does not exist in {@code jtx}<a name="line.78"></a>
<span class="sourceLineNo">079</span>     * @throws org.jsimpledb.core.UnknownFieldException  if {@code jobj} has a schema version that<a name="line.79"></a>
<span class="sourceLineNo">080</span>     *  does not contain the affected field, or in which the affected field has a different type<a name="line.80"></a>
<span class="sourceLineNo">081</span>     * @throws RuntimeException if there is some other incompatibility between this change and the target object,<a name="line.81"></a>
<span class="sourceLineNo">082</span>     *  for example, setting a list element at an index that is out of bounds<a name="line.82"></a>
<span class="sourceLineNo">083</span>     * @throws org.jsimpledb.kv.StaleTransactionException if {@code jtx} is no longer usable<a name="line.83"></a>
<span class="sourceLineNo">084</span>     */<a name="line.84"></a>
<span class="sourceLineNo">085</span>    public abstract void apply(JTransaction jtx, JObject jobj);<a name="line.85"></a>
<span class="sourceLineNo">086</span><a name="line.86"></a>
<span class="sourceLineNo">087</span>    /**<a name="line.87"></a>
<span class="sourceLineNo">088</span>     * Apply this change to the object associated with this instance in the given transaction.<a name="line.88"></a>
<span class="sourceLineNo">089</span>     *<a name="line.89"></a>
<span class="sourceLineNo">090</span>     * &lt;p&gt;<a name="line.90"></a>
<span class="sourceLineNo">091</span>     * This is a convenience method, equivalent to:<a name="line.91"></a>
<span class="sourceLineNo">092</span>     * &lt;blockquote&gt;&lt;code&gt;<a name="line.92"></a>
<span class="sourceLineNo">093</span>     * apply(jtx, this.getJObject());<a name="line.93"></a>
<span class="sourceLineNo">094</span>     * &lt;/code&gt;&lt;/blockquote&gt;<a name="line.94"></a>
<span class="sourceLineNo">095</span>     *<a name="line.95"></a>
<span class="sourceLineNo">096</span>     * @param jtx transaction in which to apply this change<a name="line.96"></a>
<span class="sourceLineNo">097</span>     * @throws IllegalArgumentException if {@code jtx} is null<a name="line.97"></a>
<span class="sourceLineNo">098</span>     */<a name="line.98"></a>
<span class="sourceLineNo">099</span>    public void apply(JTransaction jtx) {<a name="line.99"></a>
<span class="sourceLineNo">100</span>        if (jtx == null)<a name="line.100"></a>
<span class="sourceLineNo">101</span>            throw new IllegalArgumentException("null jtx");<a name="line.101"></a>
<span class="sourceLineNo">102</span>        this.apply(jtx, this.getJObject());<a name="line.102"></a>
<span class="sourceLineNo">103</span>    }<a name="line.103"></a>
<span class="sourceLineNo">104</span><a name="line.104"></a>
<span class="sourceLineNo">105</span>    /**<a name="line.105"></a>
<span class="sourceLineNo">106</span>     * Apply this change to the transaction associated with the current thread.<a name="line.106"></a>
<span class="sourceLineNo">107</span>     *<a name="line.107"></a>
<span class="sourceLineNo">108</span>     * &lt;p&gt;<a name="line.108"></a>
<span class="sourceLineNo">109</span>     * This is a convenience method, equivalent to:<a name="line.109"></a>
<span class="sourceLineNo">110</span>     * &lt;blockquote&gt;&lt;code&gt;<a name="line.110"></a>
<span class="sourceLineNo">111</span>     * apply(JTransaction.getCurrent())<a name="line.111"></a>
<span class="sourceLineNo">112</span>     * &lt;/code&gt;&lt;/blockquote&gt;<a name="line.112"></a>
<span class="sourceLineNo">113</span>     *<a name="line.113"></a>
<span class="sourceLineNo">114</span>     * @throws IllegalStateException if there is no {@link JTransaction} associated with the current thread<a name="line.114"></a>
<span class="sourceLineNo">115</span>     */<a name="line.115"></a>
<span class="sourceLineNo">116</span>    public void apply() {<a name="line.116"></a>
<span class="sourceLineNo">117</span>        this.apply(JTransaction.getCurrent());<a name="line.117"></a>
<span class="sourceLineNo">118</span>    }<a name="line.118"></a>
<span class="sourceLineNo">119</span><a name="line.119"></a>
<span class="sourceLineNo">120</span>    /**<a name="line.120"></a>
<span class="sourceLineNo">121</span>     * Apply this change to the specified object.<a name="line.121"></a>
<span class="sourceLineNo">122</span>     *<a name="line.122"></a>
<span class="sourceLineNo">123</span>     * &lt;p&gt;<a name="line.123"></a>
<span class="sourceLineNo">124</span>     * This is a convenience method, equivalent to:<a name="line.124"></a>
<span class="sourceLineNo">125</span>     * &lt;blockquote&gt;&lt;code&gt;<a name="line.125"></a>
<span class="sourceLineNo">126</span>     * apply(obj.getTransaction(), jobj);<a name="line.126"></a>
<span class="sourceLineNo">127</span>     * &lt;/code&gt;&lt;/blockquote&gt;<a name="line.127"></a>
<span class="sourceLineNo">128</span>     *<a name="line.128"></a>
<span class="sourceLineNo">129</span>     * @param jobj object to which to apply this change<a name="line.129"></a>
<span class="sourceLineNo">130</span>     * @throws IllegalStateException if there is no {@link JTransaction} associated with {@code jobj}<a name="line.130"></a>
<span class="sourceLineNo">131</span>     * @throws IllegalArgumentException if {@code jobj} is null<a name="line.131"></a>
<span class="sourceLineNo">132</span>     */<a name="line.132"></a>
<span class="sourceLineNo">133</span>    public void apply(JObject jobj) {<a name="line.133"></a>
<span class="sourceLineNo">134</span>        if (jobj == null)<a name="line.134"></a>
<span class="sourceLineNo">135</span>            throw new IllegalArgumentException("null jobj");<a name="line.135"></a>
<span class="sourceLineNo">136</span>        this.apply(jobj.getTransaction(), jobj);<a name="line.136"></a>
<span class="sourceLineNo">137</span>    }<a name="line.137"></a>
<span class="sourceLineNo">138</span><a name="line.138"></a>
<span class="sourceLineNo">139</span>// Object<a name="line.139"></a>
<span class="sourceLineNo">140</span><a name="line.140"></a>
<span class="sourceLineNo">141</span>    @Override<a name="line.141"></a>
<span class="sourceLineNo">142</span>    public boolean equals(Object obj) {<a name="line.142"></a>
<span class="sourceLineNo">143</span>        if (obj == this)<a name="line.143"></a>
<span class="sourceLineNo">144</span>            return true;<a name="line.144"></a>
<span class="sourceLineNo">145</span>        if (obj == null || obj.getClass() != this.getClass())<a name="line.145"></a>
<span class="sourceLineNo">146</span>            return false;<a name="line.146"></a>
<span class="sourceLineNo">147</span>        final Change&lt;?&gt; that = (Change&lt;?&gt;)obj;<a name="line.147"></a>
<span class="sourceLineNo">148</span>        return this.jobj.equals(that.jobj);<a name="line.148"></a>
<span class="sourceLineNo">149</span>    }<a name="line.149"></a>
<span class="sourceLineNo">150</span><a name="line.150"></a>
<span class="sourceLineNo">151</span>    @Override<a name="line.151"></a>
<span class="sourceLineNo">152</span>    public int hashCode() {<a name="line.152"></a>
<span class="sourceLineNo">153</span>        return this.jobj.hashCode();<a name="line.153"></a>
<span class="sourceLineNo">154</span>    }<a name="line.154"></a>
<span class="sourceLineNo">155</span>}<a name="line.155"></a>
<span class="sourceLineNo">156</span><a name="line.156"></a>




























































</pre>
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